A safety ski binding of the above-mentioned type is described for example in German OS No. 19 51 430. In this conventional design, the sole plate is secured to the upper side of the ski. Two levers are swingably supported for movement out on the sole plate about axes which extend perpendicularly with respect to the upper side of the ski, which levers each carry one of the holding jaws which, in the downhill skiing position, grip around the shoe fitting which is secured on the ski shoe sole. Control ramps are provided on the levers, which ramps cooperate with control ramps on a power-transmitting member which can be moved in the direction of the tip of the ski against the force of a spring. During a release, the shoe fitting which is secured on the ski shoe swivels one or both levers, which effects or effect through the control ramps, a movement of the power-transmitting member against the force of the spring. The two holding jaws laterally engage the shoe fitting on the shoe sole. In order to avoid a looseness of the ski shoe in the binding, it is therefore necessary to additionally support the ski shoe on the ski in the region in front of the binding. This support is provided by a guide plate which is secured to the ski. However, during a release, the friction which occurs additionally between the ski shoe sole and the guide plate effects an increase of the release forces. Furthermore, the shoe fitting, which projects both laterally beyond the edges of the ski shoe sole and also downwardly beyond the remaining sole area, effects a high degree of discomfort during walking in the ski shoes, and also effects a clogging of the shoe fitting with dirt, snow and the like, as well as the risk of the shoe fitting getting caught on obstacles. A further disadvantage of this binding is that there is no precisely definable vertical axis capable of being associated with the ski shoe during a torsion release.
The purpose of the invention is now to provide a safety ski binding of the above-mentioned type such that it does not have the disadvantages of the conventional solution. Furthermore, a reliable hold of the ski shoe without its additional support is assured.
The set purpose is inventively attained by providing a shoe fitting which is secured to the ski in the region of the shoe sole and being arranged within the confines of the sole dimension and preferably within the plane defined by the sole. The sole fitting has two rear holding elements and at least one front holding element, which holding elements cooperate with two rear holding jaws and at least one front holding jaw, whereby the front holding jaw is supported for limited pivotal movement about a vertical axis which extends preferably coaxially of the tibia axis of the leg of the user.
Through the inventive measure, a safety ski binding with a sole plate is created, which assures a wobble-free hold of the ski shoe in the binding without necessitating an additional support of the ski shoe on the upper side of the ski. Therefore, a good centering and a reliable holding of the ski shoe in the holding jaw of the binding exists. Due to the fact that at least three holding elements are provided on the shoe fitting, the shoe fitting can be designed such that it does not project laterally beyond the shoe sole and also can be wholly housed accordingly within the confines of the shoe sole and in a recess therein. Furthermore, through a provision of a swingable support of the front holding jaw, there is provided a defined axis of rotation during a torsion release or a combined torsion and forward release.
A further characteristic of the invention consists in the two rear holding jaws being constructed as control hooks, which are arranged or secured on a control part, which control part is supported on the slide member, both of which can be simultaneously moved against the force of the release spring in a longitudinal direction of the ski. The control hooks are therefore coupled in a particularly simple manner with the slide member which is movable against the force of the release spring and can be moved against the force of the spring into their open position.
The front holding jaw is inventively constructed as a cup with preferably two holding zones for two front holding elements on the shoe fitting, which cup is supported for limited pivotal movement about the axis of a swivel pin which forms the vertical axis, which swivel pin is supported in the front area of a carriage which is supported for limited movement relative to a ski-fixed housing in the longitudinal direction of the ski. Also through this a particularly simple construction of the front holding jaw and a structurally simple swingable support of the same about the vertical axis is assured.
A further thought of the invention consists in the holding elements on the shoe fitting which cooperate with the control hooks or the holding zones of the cup, viewed in the sole plane, form the corner points of a rectangle and are constructed as rounded extensions of the shoe fitting, which extensions extend away from the ski shoe and in pairs from one another. With this a self-centering of the ski shoe during a stepping into the binding is assured.
A release of the ski shoe both during a torsional fall (that is, a fall wherein the human leg is subjected to a torsional stress) and also during a forward bending fall (that is, a fall wherein the human leg is subjected to a forward bending stress) is now inventively assured by the two control hooks having control surfaces thereon which control a torsion release and a forward bending release and the holding zones of the cup have the control surfaces thereon which control a rearward bending fall, which control surfaces are constructed on the upper region of the holding zones as inclined surfaces which extend in a direction toward the control hooks. In all of these fall directions or also during a combined fall direction, therefore, a movement of the control part with the control hooks against the force of the release springs is assured. The design of the control surfaces occurs, of course, in a manner such that during a torsion release there exists approximately 1/4th of the release force of a forward bending release.
According to a further characteristic of the invention, the carriage which has the swivel pin mounted thereon is movably guided on a guideway on a base plate of the ski-fixed housing, whereby the control part is guided in a slotted hole in each of the side walls of the carriage by means of two peglike extensions. This structure provides a support of the control part on the carriage, which support assures, for the release of the ski shoe a movement of the control hooks relative to the carriage or to the cup, which cup is connected to the carriage through the swivel pin.
A further thought of the invention consists in the control part engaging with its surface area not facing the slide member a support nose preferably arranged on the guideway of the ski-fixed housing. This structure enables the ski shoe, even during a head-on collision of the ski with an obstacle, to be reliably released. In this case, namely, the ski shoe moves the front holding jaw, which is constructed as a cup, together with the carriage in a direction toward the tip of the ski, whereby through the control part which is maintained in a fixed position by the support nose, a compressing of the release springs occurs and the distance between the cup and the control hooks which are secured on the control part is enlarged so much that a release of the ski shoe is assured.
In order to move the binding into a position ready for the ski shoe to step thereinto, it is inventively provided that the control part can be supported by means of a locking surface on a locking step of the slide member, that the locking step on the slide member can be released, preferably by means of a release lever which is supported on the ski-fixed housing, from engagement with the locking surface on the control part, that the surface area of the control part facing the support nose is rounded concentrically with respect to the peglike extensions, and that on the underside of the control part there is connected one end of at least one tension spring, the other end of which is connected to a shoulder on the carriage. Therefore, as soon as the support of the control part on the slide member is cancelled, the tension springs swing the control part or the control hooks into the open position, and the binding is ready for the ski shoe to step thereinto.
A stepping into the binding inventively requires no renewed operation of the release lever since a control slope is provided on the control part above its locking surface, which slope slidingly cooperates with a leading slope provided below the locking step on the slide member.
For the elastic return of the swivel pin to its initial position, there is provided, according to a further characteristic of the invention, two elastic elements which are each active between the carriage and an abutment shoulder on the swivel pin.
A further advantage of the invention consists in a sole plate being secured to the carriage, which sole plate has a hole therein receiving a cylindrical hub on the swivel pin therein, which hub supports a cup thereon, and which sole plate is provided with recesses or notches which facilitate a longitudinal movement of the control hooks. A penetration of snow and dirt into the binding area is thus avoided and, therefore, the function of the binding is not influenced.